Piston pumps are known in which a piston is reciprocally slidable within a piston chamber formed in a piston chamber-forming body so as to dispense flowable materials. In the context of dispensers for flowable material, notably hand soap dispensers, disposable plastic pumps are known which may be coupled to a reservoir containing fluid to be dispensed with the entirety of the reservoir and the plastic pump forming a cartridge that is replaceable and disposable after use. Plastic pumps of these type include those taught in the following U.S. patents to Ophardt: U.S. Pat. No. 5,975,360 issued Nov. 2, 1999; U.S. Pat. No. 6,601,736 issued Aug. 5, 2003; U.S. Pat. No. 7,267,251 issued Sep. 11, 2007; U.S. Pat. No. 7,303,099 issued Dec. 4, 2007 and U.S. Pat. No. 7,377,405 issued May 27, 2008, the disclosures of which are incorporated herein by reference. Piston pumps of the type disclosed in these patents are useful for engagement with and removal from fluid dispensers in a manner as disclosed in U.S. Pat. No. 5,431,309 to Ophardt issued Jul. 11, 1995 and for use in preparing a replaceable reservoir as in a manner disclosed in U.S. Pat. No. 5,489,044 to Ophardt issued Feb. 6, 1996, the disclosures of which are also incorporated herein by reference.
Replaceable fluid cartridges including a fluid filled reservoir with a piston assembly are known to be filled, shipped and stored filled with fluid and preferably with a separate, removable protective cap over the piston protecting the piston and the pump assembly. To use such a cartridge, the protective cap is removed and the reservoir and pump assembly are engaged with the dispenser with the dispenser typically supporting the reservoir and coupling the piston of the pump assembly with an actuator mechanism. Once the fluid in the reservoir has been exhausted, the cartridge comprising the reservoir and pump assembly is removed from the dispenser and replaced by another cartridge.
The present inventor has appreciated a number of disadvantages which arise with such prior art arrangements.
One disadvantage is that a user in attempting to ready a cartridge for use may remove not only the protective cap but also both the protective cap and the piston, with the removal of the piston rendering the pump inoperative. Another disadvantage is that a user may, after removing the cap, inadvertently withdraw the piston from the pump assembly as, for example, by incorrectly carrying the reservoir and its pump assembly merely by the piston. Another disadvantage is that when the piston may be removed from the pump assembly, removal of the piston out from the piston assembly can damage the piston or other components of the pump assembly and render the pump assembly inoperative or resulting in reinsertion of the piston into the piston pump which can cause damage preventing proper pump operation. Another disadvantage is that a user attempting to couple the cartridge to a dispenser may have the piston catch in an improper manner on the dispenser as on its activation mechanism such that the piston is damaged during installation or becomes engaged with the dispenser in a manner that prevents proper operation.
Another disadvantage is that during removal of the cartridge from the dispenser, a user may incorrectly remove the cartridge in a manner which damages the pump assembly as, for example, by leaving the entire piston or a portion of the piston in the dispenser damaging the dispenser or preventing proper function of the dispenser when the next cartridge is installed or attempted to be installed.
Previously known devices may provide a protective cap which encloses a discharge outlet portion of a piston pump and must be removed in order for use of the piston pump. The present inventor has appreciated the disadvantage that such protective caps provide an additional component which must be manufactured, assembled and discarded. Such protective caps also suffer the disadvantage that a user may be confused as to what must be removed and discarded with the disadvantage that sometimes not only the cap but also the piston itself is discarded rendering the pump inoperative.
The present inventor has appreciated the disadvantage that in the context of disposable pumps, each separate element which must be manufactured and then handled during assembly increases the cost.